If you want a cheap flight from Cardiff to Beijing, you've got zero airlines to choose from.
Make sure you use the search options above to search for flights to other airports in Beijing, not just Beijing Capital Int. Airport. The more options you look at, the better your chance of finding a cheap deal.
If you're planning on going to Beijing during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.